Aortic lancet

ABSTRACT

A system for making a precise incision and circular hole in a vessel wall, such as the aorta, that eliminates lateral side notches from the aortotomy. In one aspect, the system includes a surgical knife or lancet having a blade surrounded by a retractable shield. In one aspect, the system includes a tissue punch having a rotating circumferential edge for receiving a parabolic-shaped anvil having an anvil cutting edge. The anvil is placed through an incision made by a knife and actuated to produce a hole in the vessel wall.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention is directed generally to methods and apparatus foreffectuating surgical incisions. More specifically, the presentinvention is related to methods and apparatus for creating a hole in avessel wall including an aorta wall.

2. Description of Related Art

During surgical procedures, such as placement of a ventricular assistdevice, blood vessel anastomosis, aortotomy, gastrotonomy, enterotomy,or access to other hollow organs and vessels, it is useful to havespecialized tools to create a circular opening in the wall of the vesselor organ. Tools have been developed for use in surgery that create suchopenings. For example, often the goal of heart surgery is to produce ablood flow path around the diseased areas of coronary arteries. Asaphenous vein graft can be used by forming an opening in the wall of anascending aorta, and anastomosing the opening to a proximal end of thesaphenous vein. To form the opening in the wall of the aorta, anincision can be made using surgical scalpels and/or scissors. An aorticpunch can then be used in order to attempt to obtain a clean, accuratesomewhat larger opening in the aortic wall. Obtaining a clean andaccurate opening is extremely important since an opening which is notformed cleanly and accurately often is frayed, albeit microscopically.As a result, the connection of the proximal end of the saphenous veinthereto may not be as reliable, and complications during or aftersurgery may result. Because heart surgery necessarily often entails adifference between life and death of a patient, it is extremelyimportant to maximize the probability of success of every aspect of thesurgical procedure. To this end, it is desirable to try to obtain asclean and as accurate an opening as possible in the wall of the aortabefore grafting the saphenous vein thereto.

Once such procedure is described and illustrated in U.S. Pat. No.6,187,022. A conventional linear incision along an aorta vesselutilizing a conventional scalpel is first made. Such procedure requiresthe surgeon to make an educated guess as to the length of the incision.After the incision is made, a punch is inserted into the vessel wallthrough the incision to make a clean circular hole in the vessel wall.Unfortunately, the diameter of the hole made in the vessel wall issometimes less than the length of the educated-guess incision made bythe scalpel resulting in lateral nicks protruding from opposite sides ofthe hole in the vessel wall, as illustrated by FIG. 2 of the '022Patent. These nicks necessitate special suturing to prevent bloodleakage, and add points of weakness at the site of the vessel graft.Alternatively, a surgeon may make an incision that is smaller than thediameter of the punch such that lateral nicks might be avoided. However,such an incision necessitates stretching of the tissue for insertion ofthe aortic punch anvil. The stretching of the tissue can decrease thepatency of the resulting graft or cause aortic dissection wherein thelayers of the aortic wall separate from one another. The '022 Patent'ssolution to this problem is to use a cruciate-shaped blade to make across-shaped incision for the initial incision into the vessel wall, andsubsequently completing the opening with an aortic punch.

An additional problem a surgeon faces with making such incision is thatthe heart, in some procedures, is not arrested and is permitted to beat,which can impart some movement on the vessel that the surgeon isattempting to make an incision. Such movement can make an accurateincision more difficult. Further, if a surgeon applies too much pressureand pushes the scalpel or blade too far into the vessel, damage to theopposite or back wall of the vessel can occur. Consequently, a needexists for an improved incision device or lancet. The improved deviceshould protect the surgeon's fingers from being cut with the blade, andit should provide a way to minimize or eliminate cuts that could beaccidentally made during surgery. The improved device should minimize oreliminate nicks outside the diameter of the punched hole in the vesselwall and should provide a clean cut.

As discussed above, after an incision is made, an aortic punch is usedto obtain the opening in the aortic wall. One example of such punch isillustrated by U.S. Pat. No. 5,827,316 (the '316 Patent). One problemwith prior art punches is that the distal end of the anvil is typicallyflat, or has a tip with a vertex having a large angle. As a result,sufficient pressure must be supplied to penetrate the incision. As theamount of pressure required increases, the potential for an undesirablefissure or tear in the vessel wall increases as well. Further,additional pressure can cause undesirable stretching of the tissueremaining after the hole in the vessel has been made. Consequently, aneed exists for an aortic punch that can minimize or eliminate fissures,or tears, and/or stretching that can occur in a vessel wall.

SUMMARY OF THE INVENTION

The present invention relates to an improved system for making a preciseincision and circular hole in a vessel wall. In one aspect, the systemcomprises a lancet having a retractable shield surrounding a blade. Theretractable shield helps to prevent any accidental cutting that canoccur during surgical conditions. When an incision is made, the shieldsimultaneously retracts as the blade penetrates the front vessel wall.The blade length is less than the inside diameter of the vessel wall toprevent accidental penetration of the back vessel wall. In one aspect,the system comprises a punch having a tapered cutter with acircumferential edge for receiving an anvil cutting edge. The anvil isplaced through the incision in the front vessel wall and actuated tocause a helical shearing force as the anvil cutting edge axially slidespast the rotary circumferential cutting edge to produce a clean-cut holein the vessel wall.

The above as well as additional features and advantages of the presentinvention will become apparent in the following written detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the invention are setforth in the appended claims. The invention itself, however, as well asa preferred mode of use, further objectives and advantages thereof, willbe best understood by reference to the following detailed description ofillustrative embodiments when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is an exploded perspective view of the lancet in accordance withone embodiment of the present invention.

FIG. 2 is a perspective view of the lancet in accordance with oneembodiment of the present invention.

FIG. 3 is a partial side view of the lancet inserted in a vessel wall inaccordance with one embodiment of the present invention.

FIG. 4 is a partial side view of the lancet in accordance with oneembodiment of the present invention.

FIG. 5 is a side view of the aortic punch in accordance with oneembodiment of the present invention.

FIG. 6 is a partial side view of the aortic punch inserted in a vesselwall in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 1 is an exploded perspective view of the lancet in accordance withone embodiment of the present invention. The lancet 100 comprises ablade 120 attached to a handle 110. In one embodiment, the handlecomprises a first section and a second section that can be removablysnap-fit together. In one embodiment, the first section of the handle110 comprises at least one and preferably two male members 112 disposedthrough an aperture 122 in the blade 120 and into a female member 114 inthe second section to attach the blade 120 to the handle 110. The blade120 thereby protrudes from the handle 110. A retractable blade shield130 is slidably attached to the handle 110 and surrounds the blade 120.In one embodiment, the blade shield 130 is clear or transparent so thatthe blade 120 is visible.

The blade shield 130 helps to minimize accidental cutting that can occurin surgical conditions. For example, it should be noted that duringsurgical conditions, slippery fluids such as blood and sudden movementscreated by a beating heart in conjunction with the decreased tactilefunction that can occur with a surgeon wearing latex gloves createconditions that can result in an accidental cutting. Further, the bladeshield 130 can be gripped by a surgeon's fingers to aid in initialplacement of the blade 120. Thus, the blade shield 130 can help protectthe surgeon's fingers during surgical conditions and/or ensure that anincision is made only at the desired place on the vessel. In oneembodiment, the retractable blade shield 130 is kept in an extendedposition around the blade 120 by a spring, or other equivalentresistance means. In one embodiment, the spring 140 comprises aresistance that is less than the insertion force required to make anincision into a vessel.

FIG. 2 is a perspective view of the lancet in accordance with oneembodiment of the present invention. FIG. 4 is a partial side view ofthe lancet in accordance with one embodiment of the present invention.Referring to FIGS. 2 and 4, a protective cover 200 can be press-fit overthe retractable blade shield and blade and over a portion of the handleas an additional safety precaution. Further, the protective cover 200can protect the blade 122 from potential contaminants when the lancet100 is not in use.

FIG. 3 is a partial side view of the lancet inserted in a vessel wall inaccordance with one embodiment of the present invention. As depicted inFIG. 3, the lancet is shown without a protective cover and with theretractable shield 130 in the fully retracted position. The blade 120having a blade length BL is thereby exposed within the vessel 300. Theblade length BL is defined as the length of the blade 130 that isexposed when the blade shield is fully retracted. In one embodiment, theblade length BL is between about 1 millimeter and about 20 millimetersand more preferably between about 5 millimeters and about 15millimeters. In one embodiment, the blade length BL is dimensioned suchthat during blade penetration of the front vessel wall 310, the backwall 320 cannot be penetrated. Consequently, in one embodiment, theblade length BL is substantially less than or equal to the inner wallvessel diameter D. In one embodiment, the blade comprises a primary andsecondary blade similar to that disclosed in U.S. Pat. No. 6,187,022 andmakes a cruciate-shaped incision having an incision diameter ID. In oneembodiment, the end of the handle is tapered 160 to provide a surgeonwith a better finger grip.

FIG. 5 is a side view of the aortic punch in a vessel wall in accordancewith one embodiment of the present invention. FIG. 6 is an enlargedpartial side view of the aortic punch in accordance with one embodimentof the present invention. Referring to FIG. 5 and FIG. 6, the aorticpunch 500 is shaped and designed to be used by a surgeon using one ofhis or her hands. The aortic punch includes a thumb button 510 pushableinto an opening 512 in a finger grip body 514 which is a non-rotatingmember. A pair of finger seats 520 can be attached to the finger gripbody 514 and can be shaped to be engaged by a surgeon's fingers. Tooperate the aortic punch 500, a surgeon can grab the punch in his or herhand, place a thumb on the thumb button 510 and place both an indexfinger tip and a middle finger tip on the finger seats 520. After anincision has been made by a lancet, the surgeon can maneuver the aorticpunch 500 so that the parabolic-shaped anvil 600 on the end of the shaftis inserted into the incision in the front vessel wall 310 (shown inFIG. 3).

After the anvil 600 is inserted into the incision in the front vesselwall 310, the surgeon can push on the thumb button 510 with his or herthumb while holding the finger seats 520 with his or her fingers. As thethumb button 510 is pushed into the finger grip body 514 through theopening 512, the hollow body member 516 attached to a tapered cutter 618having a sharp circumferential edge 632 simultaneously rotates as thepiston 640 and anvil 600 moves downward through the opening defined bythe sharp circumferential edge 632. An opening in the front vessel wall310 is created by a helical shearing force as the anvil cutting edge 630axially slides past the rotating circumferential cutting edge 632. Thehelical shearing force imparted creates a clean-cut hole in the vesselwall. The helical shearing force also minimizes or eliminates fissures,tears, and/or stretching in the vessel area adjacent the hole. Thediameter of the tapered piston 640 can be sized so as to prevent fluidsand vessel tissue from entering the hollow body member 516 whilepermitting the piston 640 to slidably move in the axial direction withinthe tapered cutter 618.

The parabolic shaped anvil 600 comprises a vertex 610 at the distal endof the anvil and an anvil cutting edge 630 having an anvil diameter ADat the proximal end of the anvil 600. One advantage of the parabolicshape is that it permits easy perpendicular insertion of the anvil 600through the incision which can help to minimize or eliminate stretchingin the remaining tissue adjacent the hole formed by the anvil. The slopeof the anvil sides 620 determines the penetration angle at which theanvil enters the vessel wall 310. A smaller penetration angle (e.g.narrower parabola) results in less insertion force of the anvil 600 intothe vessel which minimizes undesirable vessel fissures and is lesslikely to cause undesirable tearing upon insertion. Consequently, arelatively longer anvil length AL can be used to provide an anvil havingthe proper anvil diameter AD at the anvil cutting edge 630 and anoptimal penetration angle.

In one embodiment, and referring to FIG. 3 and FIG. 6, the incisiondiameter ID created by the blade 120 is less than or equal to the anvildiameter AD. This advantageously provides a hole having no lateral nicksthat are common place in prior art devices. Hence, the punch of thepresent invention can be applied to a straight or cruciate incision. Oneadvantage of the helical shearing force provided by the parabolic-shapedanvil 600 of the present invention is that it permits an incisiondiameter ID to be made that is smaller than the anvil diameter AD.Smaller incision diameters are desirable because it minimizes theundesirable fissures and/or tearing in the vessel wall because lessinsertion force is required to make smaller incisions. The presentinvention thereby provides a system for making a precise incision andcircular hole in the aorta that eliminates lateral side notches from theaortotomy.

While this invention has been particularly shown and described withreference to a preferred embodiment, it will be understood by thoseskilled in the art that various changes in form and detail may be madetherein without departing from the spirit and scope of the invention.

1. A lancet comprising: a blade having a blade length attached to ahandle; a retractable shield attached to said handle wherein saidretractable shield surrounds said blade.
 2. The lancet of claim 1wherein said blade comprises a multi-bladed configuration.
 3. A lancetof claim 1 wherein said blade length is dimensioned such that a backwall of a vessel opposing blade insertion cannot be penetrated.
 4. Thelancet of claim 1 wherein said retractable shield comprises a resistancethat is less than the insertion force required to force said blade intoa vessel.
 5. The lancet of claim 1 wherein said retractable shield istransparent.
 6. The lancet of claim 1 wherein said retractable shieldfurther comprises a protective cover.
 7. The lancet of claim 1 whereinsaid retractable shield uses a spring.
 8. An aortic punch comprising: anon-rotating finger grip body having a first end and a second end; athumb button disposed on said first end wherein said thumb button can bepressed into said non-rotating finger grip body; a rotating hollow bodymember attached to said second end, wherein said hollow body memberfurther comprises a tapered cutter having a sharp circumferential edge;a piston disposed within said circumferential edge; and aparabolic-shaped anvil comprising an anvil cutting edge having an anvildiameter, wherein said parabolic-shaped anvil is in communication withsaid piston.
 9. The aortic punch of claim 8 wherein upon actuation ofsaid thumb button, said circumferential edge rotates and said anvilcutting edge axially slides past said circumferential cutting edge. 10.A method for removing a plug of tissue from a vessel wall, said methodcomprising steps of: a) piercing the wall with a lancet of claim 1 tomake an incision in a front vessel wall; b) inserting an aortic punchinto said incision; and c) actuating said aortic punch to create a holein said wall.
 11. The method of claim 10 wherein said aortic punch atstep b) is the aortic punch of claim
 8. 12. The method of claim 10wherein said lancet comprises four blades and wherein said piercing atstep a) creates a cruciate-shaped incision having an incision diameter.13. The method of claim 12 wherein said punch comprises an anvildiameter and wherein said anvil diameter is greater than said incisiondiameter.